1. Field of the Invention
The invention relates to adsorbent materials useful as filtration media, as well as smoking article filters comprising adsorbent materials.
2. Description of Related Art
Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge, roll or column of smokable material, such as shredded tobacco (e.g., in cut filler form), surrounded by a paper wrapper, thereby forming a so-called “smokable rod” or “tobacco rod.” Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element comprises plasticized cellulose acetate tow circumscribed by a paper material known as “plug wrap.” Certain filter elements can incorporate polyhydric alcohols. Typically, the filter element is attached to one end of the tobacco rod using a circumscribing wrapping material known as “tipping paper.” Descriptions of cigarettes and the various components thereof are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999). A cigarette is employed by a smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.
Certain cigarettes incorporate filter elements having adsorbent materials dispersed therein, such as activated carbon or charcoal materials (collectively, carbonaceous materials) in particulate or granular form. For example, an exemplary cigarette filter can possess multiple segments, and at least one of those segments can comprise particles of high carbon-content materials. Granules of carbonaceous material can be incorporated into “dalmation” types of filter regions using the general types of techniques used for traditional dalmation filter manufacture. Techniques for production of dalmation filters are known, and representative dalmation filters have been provided commercially by Filtrona Greensboro Inc. Alternatively, granules of carbonaceous material can be incorporated into “cavity” types of filter regions using the general types of techniques used for traditional “cavity” filter manufacture. Various types of filters incorporating charcoal particles or activated carbon types of materials are set forth in U.S. Pat. Nos. 2,881,770 to Touey; 3,101,723 to Seligman et al.; 3,236,244 to Irby et al.; 3,311,519 to Touey et al.; 3,313,306 to Berger; 3,347,247 to Lloyd; 3,349,780 to Sublett et al.; 3,370,595 to Davis et al.; 3,413,982 to Sublett et al.; 3,551,256 to Watson; 3,602,231 to Dock; 3,972,335 to Tigglebeck et al.; 5,360,023 to Blakley et al.; 5,909,736 to Stavridis; and 6,537,186 to Veluz; U.S. Pat. Publication Nos. 2003/00340085 to Spiers et al.; 2003/0106562 to Chatterjee; 2006/0025292 to Hicks et al.; and 2007/0056600 to Coleman, III et al.; PCT WO 2006/064371 to Banerjea et al. PCT WO 2006/051422 to Jupe et al.; and PCT WO2006/103404 to Cashmore et al., which are incorporated herein by reference.
It would be highly desirable to provide a cigarette possessing a filter element incorporating an adsorbent material, wherein the filter element possesses the ability to alter the character or nature of mainstream smoke passing through the filter element.